Use a custom form action in Webflow

A Webflow custom action sets your form's action and method, so the browser sends a standard HTML form POST to the URL you enter (Webflow Help Center). The Sendform endpoint accepts a standard HTML form POST. Per Webflow, submissions sent with a custom action aren't sent to or stored in Webflow, and a custom action can't be combined with Webflow or Email notifications as destinations (How do I add forms in Webflow?, checked 2026-10-20).

1. Create a form on sendform.app and copy https://sendform.app/api/public/f/YOUR_ID.
2. In the Designer, select your form on the canvas or in the Navigator and open the Settings panel.
3. If Webflow or Email notifications are listed under Send to, remove them. Webflow doesn't allow them together with a custom action.
4. Click the add icon next to Send to and choose Custom action.
5. Paste your endpoint URL, choose POST and click Save.
6. Name each field exactly as you want it stored, e.g. name, email, message.
7. Optional: set your thank-you page under Redirect after submit in your Sendform form settings.
8. Publish and submit a test from the published site.

After submitting, the visitor leaves the page, so set a thank-you page: use the redirect in your Sendform settings; otherwise Sendform shows its own customisable thank-you page.

Sendform checks every submission for spam on its own server (a heuristic score, duplicate and disposable-email checks, your blocked words), so the basic filter needs nothing added to the Webflow form. Rate limits apply too, and Cloudflare Turnstile is optional. Spam never counts toward your quota.

• Custom action can't be added: remove the Webflow and Email notifications destinations first.
• Nothing arrives: check URL, POST, and that you republished.
• Fields blank: set the Name on each input.